In the art of air conditioning apparatus or systems, otherwise known as heating, ventilating and air conditioning (HVAC) equipment, improvements have provided systems which operate with thermostats and similar sensors which transmit digital signals to a system main controller. In the event that a thermostat or other sensor or control feature which normally sends digital signals is not available, is defective or becomes disconnected from the system controller it is not possible to operate the air conditioning system with a simple timer or manually actuated switch. Accordingly, there has been a need to develop a means and method for operating digitally controlled HVAC equipment in a so called contingency mode when a thermostat or similar type controller is not functioning properly, is not connected to the system controller or is currently not installed in the space or spaces for which the air conditioning equipment is to service. However, the present invention provides for operating a unit of air conditioning equipment or system of the general type described above in such a contingency mode.